Method of producing particulate-reinforced composites and composites produced thereby

Abstract

A process for producing particle-reinforced composite materials through utilization of an in situ reaction to produce a uniform dispersion of a fine particulate reinforcement phase. The process includes forming a melt of a first material, and then introducing particles of a second material into the melt and subjecting the melt to high-intensity acoustic vibration. A chemical reaction initiates between the first and second materials to produce reaction products in the melt. The reaction products comprise a solid particulate phase, and the high-intensity acoustic vibration fragments and / or separates the reaction products into solid particles that are dispersed in the melt and are smaller than the particles of the second material. Also encompassed are particle-reinforced composite materials produced by such a process.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit of U.S. Provisional Application No. 61 / 411,961, filed Nov. 10, 2010, the contents of which are incorporated herein by reference.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH[0002]This invention was made with government support under Contract No. DE-EE0001100 awarded by U.S. Department of Energy. The Government has certain rights in the invention.BACKGROUND OF THE INVENTION[0003]The present invention generally relates to particle-reinforced composite materials and methods for the production. More particularly, this invention relates to a process of producing composite materials that utilizes an in situ reaction process to produce a uniform dispersion of a fine particulate reinforcement phase.[0004]There is considerable interest in processes for producing particulate-reinforced metal matrix composite (MMC) components for a large array of metals and alloys for the purpose of increasing their strength, h...

AI Technical Summary

Benefits of technology

[0011]A technical effect of the invention is the ability to use high-intensity acoustic (ultrasonic) vibration to break up or separate reaction products (usually small particles) from larger particles initially added into a melt (molten material) during a chemical reaction process. The resultant particles are much smaller than the particles initially added into the melt. The application of acoustic vibration can also encourage the nucleation of particle formation from the dissolved elements in the melt on cooling to form small particles, as well as break up larger reaction products (particles) into smaller ones.

Problems solved by technology

As a result, limited types of spherical particles have been formed in molten metals.

Furthermore, the reactions occur at extremely high temperatures, and therefore it can be difficult to use these processes to produce high quality, lightweight matrix composites, for example, aluminum or magnesium matrix composites.

However, stirring methods are typically only capable of dispersing particles larger than ten micrometers.

Liquid stirring methods are known to be not generally effective for separating particles smaller than ten micrometers from their agglomerates, breaking up individual particles from their clusters formed during a self-propagating high-temperature synthesis (SHS) process, and breaking up the reaction products (smaller particles) during the chemical reaction of an in-situ direct melt process.

It is believed that this limitation is attributable to the insufficiency of shear stresses generated by melt stirring.

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